Exuberant and engaging, River is also fighting aplastic anemia, a disease caused by a failure of bone marrow that results in a lack of blood cells and platelets.

For about two months, River has had his blood screened once or twice a week and transfusions of platelets. This week, he underwent immunosuppression treatments, which shut down his immune system to try and restart marrow growth.

Through it all, his mother Tamothy Louten said, “River’s spirit is truly unchanged.”

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To help cover the costs of a bone marrow transplant in Boston and associated expenses for his mother to stay there while River is hospitalized, a fundraiser will be held from 7-11 p.m. Nov. 16 at the Portland Club, 155 State St. in Portland. The benefit is open to the public, with a suggested donation of $10-$20.

“This will be a celebration of life and hope,” Louten said.

Friends and artists from Harpswell, Augusta and other towns have donated their art and time to a silent auction to raise money for River’s care and expenses. The River Louten Benefit Gala will also feature food and live music.

There will also be marrow screenings for possible donors by Paul Grenier of the National Marrow Donor Program. The screening requires a swab of cheek cells and places a person on the national donor registry.

The best possible donor match for River will rank 10 of 10 on a scale measuring human leukocyte antigen. Even if a perfect match is not found at the Nov. 16 screenings, marrow matches for other patients of diseases, including leukemia, may be found.

Despite low red blood cell counts that can inhibit oxygen flow and low counts of platelets that help blood to clot, River enjoys outdoor play and likes to walk on the beach or at Scarborough Marsh, his mother said.

“We can do things within reason, we play a lot of T-ball on the grass,” she said.

“I like to do jumping jacks,” River added.

Because of his reduced ability to fight infections and illnesses, River no longer attends day care. When Louten, a part-time pediatric nurse, and her husband, Danny, a graphic designer, both have to work, her mother or one of River’s former day care instructors help care for him.

The aplastic anemia was discovered after River had an allergic reaction to fish several months ago. He is also allergic to nuts, eggs, poultry and sunflower and sesame seeds.

The reaction to fish caused bruising and pinprick-sized spots on his torso from burst blood vessels, called petechiae. On the Monday after his reaction, Louten said her son’s pediatrician took a blood sample. When the results were known the next day, she was told to take him to an emergency room because his platelet count was dangerously low.

By that Wednesday, he was seeing doctors at the Maine Children’s Cancer Program in Scarborough. It was quickly determined that River did not have leukemia, but his bone marrow was failing.

Louten said a marrow transplant offers promising results. A transplant also means one to three months of hospitalization in Boston, with Louten staying close by and Danny Louten visiting when he can.

“His youth means chances of recovery are very strong,” she said.

News about River and more information about the benefit auction and gala can be found at the River Louten Fund page on Facebook.